Melanotan 2 FAQ: Straight Answers, Cited
What is Melanotan 2?
Melanotan 2 is a synthetic cyclic peptide that copies the natural pigment hormone alpha-MSH and activates the melanocortin receptors. In an early Phase I pilot study, five low subcutaneous doses darkened skin in 2 of 3 healthy men with no sun, and the men also reported spontaneous erections [4]. It is not approved for human use.
What is Melanotan 2 used for in research?
In the published literature, Melanotan 2 has been studied for skin pigmentation (the original pilot study [4]), for erectile dysfunction in a small controlled trial [5], and — in animals — for appetite and weight, energy balance, nerve regeneration, and behavior. There is no approved use; the human evidence is limited to small Phase I studies.
What is the difference between Melanotan 1 and Melanotan 2?
Melanotan 1 (afamelanotide) is a linear analog with relatively MC1R-selective, mostly-pigment activity, and it is an approved drug for the rare light-sensitivity disease EPP. Melanotan 2 is cyclic and non-selective, hitting all five melanocortin receptors, so it darkens skin and also affects appetite and sexual function [3]. Only Melanotan 1 has regulatory approval.
Where is Melanotan derived from or made?
Melanotan 2 is fully synthetic — it is not extracted from any plant or animal. It was designed and synthesized at the University of Arizona in the late 1980s as a lab-made analog of alpha-MSH, the body's own pigment hormone [3]. Chemists assemble it as a freeze-dried peptide powder; it is not a natural product.
What receptors does Melanotan 2 bind?
Melanotan 2 is a non-selective agonist of all five melanocortin receptors, MC1R through MC5R [1]. MC1R drives skin and hair pigmentation; MC4R governs appetite and sexual function; MC3R handles energy balance; MC5R works in oil glands. Binding all five is why one molecule produces such a wide range of effects.
What is the molecular weight and structure of Melanotan 2?
Melanotan 2 is a cyclic heptapeptide (seven amino acids closed into a ring by a lactam bridge), with the sequence Ac-Nle4-cyclo[Asp5-His6-D-Phe7-Arg8-Trp9-Lys10]-NH2. Its molecular weight is about 1024 daltons and its formula is C50H69N15O9 [50]. The ring makes it more resistant to enzymes than the linear alpha-MSH it copies.
How do you reconstitute Melanotan 2 for research?
This site does not provide preparation, mixing, or injection instructions, because Melanotan 2 is not approved for human use. The literature describes it as a lyophilized (freeze-dried) powder that is kept cold and dry, with reconstituted peptide solutions typically refrigerated per general peptide-lab practice [43]. Beyond that physicochemical description, we give no how-to.
How does Melanotan 2 work in the body?
Melanotan 2 binds melanocortin receptors and raises cyclic AMP inside the cell. On skin pigment cells (MC1R), that triggers the PKA-CREB-MITF-tyrosinase cascade that makes dark pigment, so skin darkens without UV [2]. In the brain (MC4R), it reduces appetite and drives central pro-erectile signaling [1]. One peptide, several receptor-driven effects.
What is the melanogenesis (MC1R-cAMP-MITF) signaling cascade?
It's the chain of events that makes pigment. MC1R activation raises cyclic AMP, which activates PKA, which switches on the transcription factor CREB, which upregulates MITF — the master regulator of pigment cells — which turns on tyrosinase, the enzyme that builds melanin [2]. Melanotan 2 fires this cascade chemically, producing eumelanin without sunlight.
Does Melanotan work without sun exposure?
Yes — that is the whole point in the research. In the pilot Phase I study, subcutaneous Melanotan 2 produced measurable skin darkening in 2 of 3 men with no UV exposure at all [4]. It works by directly triggering the pigment-making cascade inside melanocytes, rather than relying on UV damage to start the process [2].
How long does it take to tan with Melanotan 2?
In the original pilot study, measurable facial and upper-body darkening appeared after only five low subcutaneous doses given over about two weeks [4]. Users commonly report visible darkening within days. The exact pace varies, and this is a description of a small study and reported experience, not a protocol or recommendation.
How long does the tan from Melanotan last? Is it permanent?
The tan is not permanent, but it long outlasts the peptide. Because melanin synthesis continues after the molecule clears the blood in hours, pigmentation persists for weeks [48]. Users frequently report the color fading slowly and patchily over weeks to months after stopping, with moles and freckles sometimes staying darker than before.
What does Melanotan do for men?
Beyond tanning, the most documented male effect is on erections. In a controlled crossover study, 0.025 mg/kg subcutaneous Melanotan 2 produced clinically apparent erections in 8 of 10 men with psychogenic erectile dysfunction, versus placebo [5]. Men also commonly report increased libido and spontaneous erections, sometimes at inconvenient times — these are reported effects, not a treatment.
Does Melanotan affect erectile function in the research?
Yes. In a double-blind, placebo-controlled crossover trial, mean firm-erection time was 38.0 minutes with Melanotan 2 versus 3.0 minutes with placebo (p=0.0045) in men with psychogenic erectile dysfunction [5]. The effect is central (brain-driven via MC4R), not a direct blood-flow effect, and the compound is not an approved erectile-dysfunction drug.
Does Melanotan cause fat loss?
In rodents, yes — but it has not been shown in controlled human studies. Melanotan 2 microinjected into the nucleus accumbens cut food intake and food-seeking in mice without causing aversion or changing metabolic rate [6]. People commonly report reduced appetite and some weight loss, but that remains anecdotal and animal-backed, not proven in humans.
Is Melanotan 2 safe to use?
Its safety is not established, and serious harms are documented. Case reports link Melanotan 2 to renal infarction and rhabdomyolysis with kidney injury [21][20], priapism [22], and changes in moles including melanoma [15]. It has no regulatory approval and online products are often impure [29]. We describe the cited risks; we do not advise use.
Does Melanotan 2 affect the kidneys?
Case reports describe serious kidney effects. A nephrology case report with literature review attributes renal (kidney) infarction to Melanotan 2 and notes prior reports of rhabdomyolysis-related kidney failure [21]. A separate case links it to systemic toxicity with rhabdomyolysis, which can damage the kidneys [20]. The mechanisms are not fully understood.
Can Melanotan affect the appearance of moles?
Yes, and this is one of the most concerning effects. Because Melanotan 2 drives pigment cells throughout the skin, case reports describe darkening of existing moles, eruptive new moles, and atypical (dysplastic) moles during use [10][13], with dermoscopy documenting real changes [14]. Any new or changing mole during or after use warrants prompt dermatology review.
What does the research say about melanotan and erythropoietic protoporphyria (EPP)?
That research is about the related drug, not Melanotan 2. Afamelanotide (Melanotan 1) — a different, MC1R-leaning analog — is approved for erythropoietic protoporphyria, a rare disorder causing painful sun reactions, based on trials and long-term observational data [37][38]. Melanotan 2 is a separate, unapproved compound; the EPP approval does not extend to it.
Is Melanotan 2 legal, and why do regulators warn against it?
Melanotan 2 is not approved by any regulator and is not legal to market for human use; it is handled as a research chemical [3]. Regulators and dermatology bodies warn against melanotan tanning products because of documented harms — changing moles, melanoma reports, and serious adverse events — and because online products are unregulated and often mislabeled [36][35].
What is the difference between Melanotan 2 and PT-141 (bremelanotide)?
PT-141 (bremelanotide) is a melanocortin agonist developed from the Melanotan 2 scaffold but tuned toward MC4R-driven sexual effects with reduced pigmentation activity, and it is an approved drug for a specific sexual-desire condition [39]. Melanotan 2 is the non-selective parent that also darkens skin and is not approved for any use. PT-141's approval does not apply to Melanotan 2.
What are typical before-and-after pigmentation results reported in studies?
In the only controlled pigmentation study, 2 of 3 healthy men showed measurable darkening of the face, upper body, and buttocks after just five low subcutaneous doses, with no sun [4]. Users also report uneven or blotchy results and darkening of moles and freckles. Controlled before-and-after data on Melanotan 2 is limited to that small Phase I study.